In conventional paint booths for vehicle bodies using robots, the guide rails are usually installed laterally on the booth floor. For different reasons, the arrangement of robot guide rails above the conveyor or even above the bodies may be more expedient, for example because they obstruct the view through the side wall of the booth and provide less access to the bodies or other application objects and/or because the higher placed robots have correspondingly improved freedom of movement, and/or because the higher placed guide rails are contaminated less by overspray which is drawn off downward by the normal airflow in the booth. Further, higher mounted robots may have the advantage that they disturb the airflow moving from the booth ceiling downward along the body sides on to the booth floor less than robots positioned on the floor next to the body, which restrict the air passage directly at the body, possibly resulting in an undesirable increase in airflow velocity.
In the case of a painting installation known from WO 2004/037430 A1, several painting robots are located on two parallel guide rails which, in turn, are mounted on a box frame positioned inside the booth having four legs connected by cross braces, in a manner similar to the known gantry robot designs.
A painting zone in a paint booth for vehicle bodies with air supply through the upper ceiling and two walk-in control areas positioned vertically one above the other is known from EP 1 263 535 B1, wherein robot guide rails raised above the conveyor are built into modular pre-assembled side wall elements of the booth. The load-bearing structures of the guide rails, in contrast to the box frame from WO 2004/037430 A1, are separated from each other in the booth interior, thus avoiding the cross-braces in the booth interior and potential problems concerning the mechanical stability of the known box frame. On the floor of this known paint booth, which is configured as usual as a grating to draw off the vertical flow of air, additional guide rails for more robots are mounted below the elevated guide rails next to the lower control area, with the robots on the lower level being painting robots, the upper robots being door or hood openers.
Paint booths for vehicle bodies having robot guide rails mounted vertically one above the other on the booth walls and with several painting zones located one after the other along the conveyor track are known from EP 0 745 429 A1.
In the case of the known paint zones have elevated robot guide rails, the side walls of the paint booth run from their upper ceiling vertically down to floor level. Since the paint booth, including the walk-in control areas, must not be too wide in view of the construction and investment cost, this results in major disadvantages for the known paint zones. Firstly, the space available for the control areas is inconveniently narrow. Secondly, if the control areas were enlarged for a given total width, the passages for the air flowing downward into the booth from the ceiling would be unacceptably restricted.
Another problem is the support required for the high-mounted guide rails, which by its nature is more difficult to achieve than in the case of guide rails on the booth floor. Adequate stability for guide rails mounted above the conveyor on a booth wall, especially without separate cross members at the height of these guide rails, was achieved until now only with undesirably high construction expense for correspondingly stable side walls.